Sheet stacking apparatus and sheet stacking method

Abstract

Disclosed is a sheet stacking apparatus which includes: a leading-edge regulating member configured to be positionally adjustable depending on a length of a plurality of corrugated paperboard sheets; a sheet stopper installed in the leading-edge regulating member in such a manner as to be movable with respect to a contact surface of the leading-edge regulating member reciprocatingly between a first position and a second position, and contactable with a leading edge of the corrugated paperboard sheet to be stacked in the hopper section; a detection section disposed upstream of the hopper section, and configured to detect a passing of each of the corrugated paperboard sheets; and a synchronization control device configured to reciprocatingly move the sheet stopper according to a detection signal, in such a manner as to allow the leading edge of the corrugated paperboard sheet to come into contact with the sheet stopper.

What is claimed is: 
     
       1. A sheet stacking apparatus comprising:
 a hopper section configured to allow a plurality of folded and glued corrugated paperboard sheets to be stacked therein from a sheet transfer section in a transfer direction and stacked therein; 
 a leading-edge regulating member configured to be positionally adjustable depending on a length of the corrugated paperboard sheets in the transfer direction so as to delimit a downstream-side position of a stacking space of the hopper section in the transfer direction, the leading-edge regulating member having a contact surface contactable with respective leading edges of the stacked corrugated paperboard sheets; 
 a sheet stopper installed in the leading-edge regulating member in such a manner as to be movable in the transfer direction with respect to the contact surface of the leading-edge regulating member reciprocatingly between a first position and a second position set downstream of the first position, and contactable with the leading edge of the corrugated paperboard sheet to be stacked in the hopper section; 
 a detection section disposed upstream of the hopper section in the transfer direction, and configured to detect a passing of each of the corrugated paperboard sheets; and 
 a synchronization control device configured to reciprocatingly move the sheet stopper according to a detection signal from the detection section, in such a manner as to allow the leading edge of the corrugated paperboard sheet to come into contact with the sheet stopper being moved from the first position toward the second position. 
 
     
     
       2. The sheet stacking apparatus according to  claim 1 , wherein the synchronization control device comprises: a drive motor; a transmission mechanism for transmitting a driving force of the drive motor to the sheet stopper; and a drive control section for controlling driving of the drive motor according to the detection signal from the detection section. 
     
     
       3. The sheet stacking apparatus according to  claim 2 , wherein the drive control section is operable to control the driving of the drive motor according to the detection signal from the detection section, in such a manner as to allow the leading edge of the corrugated paperboard sheet to come into contact with the sheet stopper when a movement speed of the sheet stopper being moved from the first position toward the second position reaches a given maximum movement speed, or when the movement speed is being reduced from the given maximum movement speed. 
     
     
       4. The sheet stacking apparatus according to  claim 3 , wherein the drive control section is operable to control a driving speed of the drive motor, in such a manner as to move the sheet stopper from the first position toward the second position at a speed equal to or less than a transfer speed of the corrugated paperboard sheets. 
     
     
       5. The sheet stacking apparatus according to  claim 2 , wherein the transmission mechanism comprises a conversion mechanism for converting a rotational motion of a rotor configured to be driven by the drive motor, to a linear reciprocating motion of the sheet stopper, the conversion mechanism being installed in the leading-edge regulating member. 
     
     
       6. The sheet stacking apparatus according to  claim 5 , wherein the drive control section is operable to control the driving of the drive motor according to the detection signal from the detection section, in such a manner as to allow the sheet stopper to perform one cycle of the reciprocating motion, every time the sheet transfer section conveys and stacks one of the corrugated paperboard sheets into the hopper section. 
     
     
       7. The sheet stacking apparatus according to  claim 2 , wherein:
 the leading-edge regulating member comprises a plurality of support portions arranged at given intervals in a width direction of the corrugated paperboard sheets being conveyed, and a frame to which the plurality of support portions are fixed; and the sheet stopper is provided in a plural number, 
 and wherein: 
 the plurality of sheet stoppers are supported, respectively, by the plurality of support portions; 
 the drive motor is fixed to the frame; and 
 the transmission mechanism is configured to transmit the driving force of the drive motor to each of the plurality of sheet stoppers. 
 
     
     
       8. The sheet stacking apparatus according to  claim 2 , wherein the drive control section is operable to sequentially execute:
 a first operation of starting the driving of the drive motor according to the detection signal from the detection section, in such a manner as to allow the sheet stopper to start the movement from the first position toward the second position; 
 a second operation of controlling the driving of the drive motor in such a manner as to increase a movement speed of the sheet stopper being moved from the first position toward the second position to reach a given maximum movement speed; and 
 a third operation of controlling the driving of the drive motor in such a manner as to reduce the movement speed of the sheet stopper from the given maximum movement speed to thereby allow the sheet stopper to reach the second position, 
 and wherein a time period from the start of the driving of the drive motor in the first operation through until the movement speed of the sheet stopper reaches the given maximum movement speed in the second operation is shorter than a time period from a time when the movement speed of the sheet stopper reaches the given maximum movement speed in the second operation through until the sheet stopper reaches the second position. 
 
     
     
       9. The sheet stacking apparatus according to  claim 8 , wherein the drive control section is operable to calculate a time period from a time when the detection section generates the detection signal through until the driving of the drive motor is started in the first operation, based on a transfer speed of the corrugated paperboard sheets, and a distance between an installation position of the detection section and a predetermined position where the leading edge of the corrugated paperboard sheet comes into contact with the sheet stopper, in the transfer direction. 
     
     
       10. The sheet stacking apparatus according to  claim 2 , wherein the drive control section is operable to sequentially execute:
 a first operation of starting the driving of the drive motor according to the detection signal from the detection section, in such a manner as to allow the sheet stopper to start the movement from the first position toward the second position; 
 a second operation of controlling the driving of the drive motor in such a manner as to increase a movement speed of the sheet stopper being moved from the first position toward the second position to reach a given maximum movement speed; 
 a third operation of controlling the driving of the drive motor in such a manner as to reduce the movement speed of the sheet stopper from the given maximum movement speed to thereby allow the sheet stopper to reach the second position; 
 a fourth operation of controlling the driving of the drive motor in such a manner as to allow the sheet stopper to start a movement from the second position toward the first position; and 
 a fifth operation of stopping the driving of the drive motor when the sheet stopper reaches the first position, and maintaining a stopped state of the drive motor until the detection signal is subsequently newly generated. 
 
     
     
       11. The sheet stacking apparatus according to  claim 9 , wherein the drive control section is operable to calculate a time period from a time when the detection section generates the detection signal through until the driving of the drive motor is started in the first operation, based on a transfer speed of the corrugated paperboard sheets, and a distance between an installation position of the detection section and a predetermined position where the leading edge of the corrugated paperboard sheet comes into contact with the sheet stopper, in the transfer direction. 
     
     
       12. A sheet stacking method for a sheet stacking apparatus, the sheet stacking apparatus comprising: a hopper section configured to allow a plurality of folded and glued corrugated paperboard sheets to be stacked therein from a sheet transfer section in a transfer direction; and a leading-edge regulating member configured to be positionally adjustable depending on a length of the corrugated paperboard sheets in the transfer direction so as to delimit a downstream-side position of a stacking space of the hopper section in the transfer direction, wherein the leading-edge regulating member has a contact surface contactable with leading edges of the corrugated paperboard sheets, the sheet stacking method comprising:
 a first movement step of, in one transfer period during which one of the corrugated paperboard sheets is stacked into the hopper section by the sheet transfer section, moving a sheet stopper reciprocatingly movable in the transfer direction with respect to the contact surface of the leading-edge regulating member, from a first position toward a second position set downstream of the first position; 
 a second movement step of, in the same transfer period as that during which the first movement step is executed, moving the sheet stopper from the second position to the first position; 
 a detection step of detecting a passing of each of the corrugated paperboard sheets at a position upstream of the hopper section in the transfer direction; 
 a synchronization step of causing the first movement step to be executed according to the detection of the passing of each of the corrugated paperboard sheets, in such a manner as to allow the leading edge of the corrugated paperboard sheet to come into contact with the sheet stopper being moved in the first movement step; and 
 a stacking step of stacking in the hopper section the corrugated paperboard sheets stopped by coming into contact with the sheet stopper.